It all boils down to greed (for tonnage) and recklessness.
The next time your in a position that calls for you to make a judgement/decision on whether you cary out an attack or move on, simply ask yourself "If this was in RL and my life as well as that of all my crew were at risk.....would I or wouldn't I?"
At least if you make the wrong decision you can always reload the game....a luxury not afforded to a Kaleun in RL.